#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
/*
修改TCP发送缓冲区和接收缓冲区的大小          
*/
#define BUFFER_SIZE 1024
int main(int argc,char*argv[])
{
    if(argc <=2)
    {
        printf("usage: %s ip_address port_number send_bufer_size \n",
        basename(argv[0]));
        return 1;
    }

    const char* ip = argv[1];
    int port = atoi(argv[2]);

   

    /*创建一个IPv4 socket地址*/
    struct sockaddr_in server_address;
    bzero(&server_address,sizeof(server_address));
    server_address.sin_family = AF_INET;
    inet_pton(AF_INET,ip,&server_address.sin_addr);
    server_address.sin_port= htons(port);

    int sock = socket(PF_INET,SOCK_STREAM,0);
    assert(sock>=0);

    int sendbuf = atoi(argv[3]);
    int len = sizeof(sendbuf);
     /*先设置TCP接收缓冲区的大小，然后立即读取之*/
    setsockopt(sock,SOL_SOCKET,SO_SNDBUF,&sendbuf,sizeof(sendbuf));
    getsockopt(sock,SOL_SOCKET,SO_SNDBUF,&sendbuf,(socklen_t*)&len);
    printf("the tcp send buffer size after setting is %d\n",sendbuf);


    if(connect(sock,(struct sockaddr*)&server_address,sizeof(server_address)))
    {
        printf("connection failed\n");
    }
    else{
        char buffer[BUFFER_SIZE];
        memset(buffer,'a',BUFFER_SIZE);
        send(sock,buffer,BUFFER_SIZE,0);

    }
    close(sock);
    return 0;
}

